- 1) Ability to give informed consent 2) 18 to 65 years of age at time of screening 3) BMI of 35 to 55 at time of screening 4) Women of childbearing potential (i.e., not post-menopausal or surgically sterilized) must agree to use adequate birth control methods. Acceptable birth control methods are limited to oral contraceptives, implants, diaphragms, IUDs, or condoms with or without spermicide, and voluntary abstinence. The method of birth control must be documented and verified at follow-up.